Dipladenia (Mandevilla) (Dipladenia) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Outdoors, give 6+ hours of direct sun to drive heavy flowering, with light afternoon shade in the hottest climates to prevent leaf scorch. When overwintered indoors, place in the brightest spot available (bright, indirect or filtered light in a sunny conservatory window). If your only bright window faces south, that's perfect for dipladenia (mandevilla) — same window any aroid would fry on.

Watering

Watering dipladenia (mandevilla): every 3-5 days in summer growth; sparingly in winter. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Keep the compost moist but never waterlogged during the growing season, letting the top 2-3 cm (1 in) dry between waterings. Reduce sharply over winter, watering just enough to stop the rootball drying out, as cool wet roots cause yellowing and bud drop.

Soil and pot

Dipladenia (Mandevilla) grows best in rich, free-draining potting mix. A loam-based or peat-free multipurpose compost opened up with perlite or grit for sharp drainage; good drainage is essential. Container plants do best in a pot with ample drainage holes, slightly pot-bound to encourage flowering. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Dipladenia (Mandevilla) sits happiest at around 40-60% humidity and 15-29°C (60-85°F). Tolerates average outdoor humidity well but appreciates moderate humidity under glass; very dry indoor air in winter encourages red spider mite, so mist or group with other plants and improve airflow. If you keep the room above 15 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed dipladenia (mandevilla) sparingly. Feed with a general-purpose liquid fertiliser monthly from spring to autumn, switching to a high-potassium (potash) feed every two weeks in summer to encourage flowering. Avoid high-nitrogen feeds, which push leafy growth at the expense of blooms. Stop feeding over winter. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on dipladenia (mandevilla) in the Growli community. Each is annotated with the most common cause so you know where to start.

• No flowers — Too little light (under 6 hours of sun), spring temperatures below ~18°C/65°F, or a high-nitrogen feed that favours foliage over blooms.
• Bud drop — Sudden swings in temperature, light or watering, or a spell of drought stress that makes the plant shed buds before they open.
• Yellowing lower leaves — Usually overwatering or cold, wet roots, especially when watering is not reduced over winter.
• Red spider mite — Hot, dry indoor air encourages mites, causing fine speckling and bleaching of the leaves and faint webbing.
• Mealybugs and whitefly — Sap-sucking pests that thrive under glass, leaving sticky honeydew and sooty mould on leaves.
• Aphids on new growth — Soft tips and flower buds attract aphids that distort growth; rinse off and treat with horticultural soap.

Companion plants

Dipladenia (Mandevilla) pairs well with Hibiscus, Bougainvillea, Lantana, Plumbago, and Trailing verbena. These are species with similar light and water needs, so you can group them in the same room or on the same shelf and water as a batch.

Propagation

Take softwood cuttings in late spring to early summer and root them in a heated propagator at 20-25°C (68-77°F); wear gloves, as the cut stems release a skin-irritating milky sap. Species can also be raised from seed in a heated propagator at 18-23°C. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Dipladenia (Mandevilla) is mildly toxic to pets. The ASPCA does not individually list Mandevilla or Dipladenia on either its toxic or non-toxic plant database, so a non-toxic claim cannot be made. It belongs to the dogbane family (Apocynaceae), which includes toxic relatives such as oleander, and the RHS notes it "may cause mild stomach upset if eaten" with sap that "may cause skin irritation." Ingestion can cause drooling, vomiting or diarrhoea in cats and dogs; the milky sap can cause contact dermatitis. Keep out of reach of pets and children, wear gloves when pruning, and contact your vet or the ASPCA Animal Poison Control Center (888-426-4435) if a pet eats any part. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Dipladenia (Mandevilla) deep-dive guides

Every aspect of dipladenia (mandevilla) care, each with its own calibrated guide:

• Dipladenia (Mandevilla) watering schedule
• Dipladenia (Mandevilla) light requirements
• Best soil mix for dipladenia (mandevilla)
• Dipladenia (Mandevilla) fertilizing guide
• When to repot dipladenia (mandevilla)
• How to propagate dipladenia (mandevilla)
• Dipladenia (Mandevilla) growth rate & size
• Dipladenia (Mandevilla) cold hardiness
• Dipladenia (Mandevilla) temperature & humidity
• Is dipladenia (mandevilla) toxic to cats & dogs?
• Getting dipladenia (mandevilla) to bloom

Related guides

Dipladenia (Mandevilla) is also known as Dipladenia, Mandevilla, rocktrumpet, Chilean jasmine, and Brazilian jasmine.

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